November 2011 Individuals with weak signaling in a nicotine-sensitive brain circuit were more vulnerable to nicotine dependence than those with stronger signaling, according to a study conducted while the subjects’ brains were in a resting state. A second resting-state study finds that the same circuit appears to mediate dependence associated with a genetic risk factor for smoking.

April 2010 Describes a literature analysis reporting on the prevalence of people with bipolar disorder who also have a substance use disorder and discusses the genetic link that may contribute to this comorbidity.